Method of forming well screens



July 28, 1936. E. E. JOHNSON METHOD OF FORMING WELL SCREENS I Original Filed April. 1, 1929 V INVENTOR. Edward E. Johnson Patented July 28, 1936 U iTED STAT ES PATENT OFFICE METHOD OF FORMING WELL SCREENS Edward E. Johnson, St. Paul, Minn assignor to Edward E. Johnson Incorporated, St. Paul,

Minn., a corporation 20 Claims.

referred to, the primary object is to provide an eiilcient construction by means of which the greatest percentage of active intake per unit of exposed area can be secured, and to further produce a structure in which the material is most effectively disposed to resist the stress involved.

An object of the invention is to provide a. method by means of which a screen wall having these characteristics can'be readily and easily fabricated.

Another object of the invention resides in pro viding a method by which a screen wall may be produced having a comparatively narrow outer face between slots and a comparatively great depth of element to resist pressure applied to the element between supports together with a method whereby the wall element can be effectively secured to the supporting member, the screen being constructed to form a continuous, direct,- unobstructed and inwardly increasing water passageway.

An object of the invention resides in using a screen element with a dovetail web and in the method of flowing a portion of the supporting rod longitudinally and pivotally against the dovetailed web at the screen element to hold the same attached thereto.

Another object .of the invention resides in using a screen element with a dovetailed web, and in the method of forming the well screen in which a portion of the body of the supporting rod is shifted bodily in a longitudinal direc- 45 tion against the dovetailed web of the spaced convolutions of the screen wall element to hold the same attached thereto.

A feature of m invention resides in the method of forming well screens in which a wedge is driven into the body of the rod adjacent a groove therein containing the web of the element to force a portion of the body of the rod into the undercut portion of the web of said element.

Another object of my invention resides in the method of forming well screens in which a second groove is cut in the rod adjacent the groove containing the wall element last placed, and in which said wedge is driven to force the portion of the body of therod standing between said grooves longitudinally of said rod and into the undercut portion of the web of said element.

A still further object of my invention resides in the method of forming well screens in which the second groove is recut to receive the web of the next convolution of the screen element and 10 I in which the operation is successively repeated for each convolution added.

A still further object of the invention resides in the method of constructing well screens in which the metal of the rod is distorted solely from the exposed side of the element as the same is coiled about the supporting rod for the purpose of securing the screen element in place.

Other objects of the invention reside in the novel combination of steps and in the various 20 ways of performing the steps, hereinafter more fully described.

In the drawing:

Fig. 1 is a perspective view of a section of a well screen constructed in accordance with my 25 improved method.

Fig. 2 is a fragmentary elevational view of one of the supporting rods and a portion of the screen wall element attached thereto, and drawn to an enlarged scale.

Fig. 3 is an elevational sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is an elevational view of one of the supporting rods showing the same grooved to receive a convolution of the wall element.

Fig. 5 is a view similar to Fig. 4 illustrating the grooved rod with one convolution of the wall element inserted therein.

Fig. 6 is a view similar to Fig. 5 showing the method of driving the standing portion of the rod lying between the grooves, laterally, with reference to the wedge and into the undercut portion of the web of the element.

Fig. 7 is a view similar to Fig. 6 showing an- 4 other method of driving a portion of the body of the rod laterally into the undercut portion of the web of the element.

In the construction of a well screen, it is highly desirable to form the screen so that the interior of the screen is perfectly clear and devoid of pockets or shelves wherein the fine particles of sand and silt which may pass through the crevices of the screen may lodge and eventually clog the crevices between the elements of the screen wall 55 wall element thereof. By my improved method a screen having these desirable characteristics can be readily manufactured and at an economical cost.

With my improved screen, a number of longltudinally disposed supporting rods ID are empioyed which are usually arranged in cylindrical formation. Upon these rods is wound a formed element II, the convolutions I! of which, as indicated in Figs. 1 and 3, are uniformly spaced from one another to form a series of divergent crevices l3 through which the water may pass from the exterior of the screen and into the interior .thereof. These divergent crevices serve to keep back the sand and at the same time admit of free passage of the water into the interior of the screen. Due to the form of the said crevices any fine particles of sand which enter the same are carried through with the water so as not to clog the screen wall and render the device inoperative.

The supporting rods l may be round, square, or hexagonal or may be shaped in any other suitable form by which sufficient rigidity will be procured to take care of the longitudinal stresses imparted to the completed screen, structure. These rods, as will become evident, serve both to support the various convolutions of the screen element and to lend rigidity to the screen structure and form in conjunction with the screen element II a composite screen wall without the use of a supporting tube or other frame structure.

The screen wall element ll of my invention is previously formed in the desired shape by drawing or rolling. This element as best shown in Fig. 3 is preferably formed of L-shaped cross section and is provided with a flange l4 having undercut edges 26 at the upper and lower portions thereof which, when the convolutions of the element are arranged adjacent one another, form the divergent crevices I3 previously referred to. The screen wall element II is further constructed with a web I 5 issuing inwardly from the flange M. This web is undercut or constructed in the form of a male dovetail designated at IS, the narrowed portion of which is attached to the flange l4. If desired, a T-shaped or similarly constructed element having a suitable dove tailed web may be employed instead of the L- shaped element.

My improved method of forming the well screen is carried out as follows: The various supporting rods I 0 are first arranged in cylindrical formation and preferably equally spaced and are disposed upon some suitable support (not shown), said rods being held in proper position thereon by any suitable means. In constructing the screen the process is preferably carried on continuously and the ribbon comprising the wall elements is wound helically around said rods and is successively dovetailed to the same during the winding operation. rods is successively grooved or notched laterally by sawing, milling or in any other suitable manner to form pairs of spaced grooves l8 and I9 which extend. completely across said rods and partially through the same. These grooves are spaced apart a distance substantially equal to the pitch of the convolutions of the screen element.

Groove i8 is preferably made with parallel sides In accomplishing this result each of they and of sufficient width to allow the widest portion of web l5 to enter and be seated snugly'in the bottom thereof. Each pair of grooves on each successive rod leads the grooves on the preceding rod so that when one round has been made, the 5 second groove I8 on any rod is spaced from the first groove l8 on said rod a distance equal to the pitch of the helix.

As the cutting of the rods l0 progresses the element II is coiled about said rods and during 10 such operation, the web I5 thereof is successively inserted into the successive grooves l8 on the various rods. The exact position of the element, when so disposed, is illustrated in Fig. 5. As the notching of the rods and the winding of the element proceeds, a wedge, diagrammatically indicated at in Fig. 6, is driven into the groove IQ of the rod into which web l5 has last been inserted, which has the eflect of forcing the intervening portion 2| of the body of the rod standing 20 between the said grooves l8 and I!) over against the sidewall of the web 15 and into contact with the dovetail portion l6 thereof, thus gripping the dovetail I 6 of the web l5 and securely locking the element II to the rod I0 with the web thereof imbedded in the respective grooves. In winding and attaching the element to the rods, suitable means are employed for progressively spacing the grooves so that the successive convolutions l2 of the element are spaced apart to provide the crevices la. The distance between the two grooves l8 and I9 is preferably substantially equal to the pitch of the convolutions of the screen wall. When the grooves are so spaced and a complete convolution of the element has been attached to all of the rods, the cutter for the groove l8 in the last rod will be directly in alignment with the groove IS in the first rod. The two cutters will then cut the rod in positions immediately following the former position, as indicated in dotted lines in Fig. 6 at 23 and 24, to form two new grooves on each particular rod, following the preceding grooves l8 on the said rod. The web l5 of the element is then laid into this second groove and the operation is repeated to lock said web therein. In this manner,the element is progressively locked to the successive rods in helical formation by a metal-to-metal dovetail joint which operation is continuous for any length of screen desired, within the limits of the supporting device on which the screenis constructed.

It will be noted that the grooves l8 after the sfirst convolution has been completed register with the grooves I9 01 the previous convolution, and that the grooves l9 are narrower than the grooves ,I8. The groove l 9 is of temporary use only and is for the accommodation of the wedge 20 in locking the dovetail web of the element to the supporting rod. This groove is purposely made narrower than groove l8 so that on the withdrawal of wedge 20 it still presents in cross section a distorted section of metal which will be completely cut away by the formation of the succeeding {groove I8. I am thus enabled to lock the successive convolutions of the screen wall element to the rods by a dovetail joint completely encompassing that portion of the web of the element lying within the circumference of the rod.

For the purpose of securing greaterstability to the joint I prefer to support the inner side of flange of element I I on the edge of rod l0 when it is locked in position as shown in Fig. 3. It will be seen from Figs. 1 and 2 that the supporting rod I0 lies wholly within the flange M of the wall element H so that the crevice I3 is open throughout itsentire length to receive the water and conduct the same into the screen proper...

If desired, the groove I 9 may be dispensed with and a sharp edged .wedge, such as designated at in Fig. '7, may be employed instead or the blunt edged wedge shown in Fig.6.. ,In suchcasathe wedge 25 is bodily driven into the rodand serves to force the metal between its point of application and the preceding groove I 8 against the dovetail l6 of the element II. This tool is applied at a distance from the center of the groove substantially equal to the pitch of the convolutions so that the distorted part or the rod may be cut away to form a groove for the reception of the next following convolution, the same as in the other method. By the use of this method, the second cut is eliminated, though greater pressure is required in eifecting the locking of the element in place upon the rod. Where the spacing of convolutions is great, the wedge may be driven into the support at a location intermediate the points of attachment of the convolutions to the support.

In the use of well screens, different widths. of crevices are required to meet with the various soil conditions and the particular requirements of the user. Such varying widths of crevices may be procured by several different methods. In one method, the width of the flange ll of the well screen element ll may be out down within certain limits as indicated at H4 in Fig. 3 so as to procure the desired spacing of the convolutions of the element without changing the pitch thereof. Screen wall elements may also be utilized in this method which have been previously formed of the right width to procure the desired spacing. In another method a screen wall element of one dimension is used and the pitch of the convolutions of the same varied by changing the lead of the coiling apparatus to procure the desired results.

Although I have described my invention as consisting in progressively dovetailing an element of the screen wall to a plurality of rods, yet I do not limit it to the development of a cylindrical form of screen as it is obviously applicable to the production of planeas well as cylindrical screen surfaces.

The method is highly advantageous in that an extremely rigid and substantial screen construction is produced. With a screen constructed by my improved method maximum capacity may be had for a given size of screen and with a minimum amount of material and labor. The method may be carried on progressively so that any length or diameter of screen may be constructed within the limits of the device on which the screen is made. With my improved method a relatively narrow outer flange for each of the convolutions may be used and suiiicient undercutting given the inner edge of the flange of the element so that the lodging of particles of sand, accidentally passing through the crevices between convolutions and the clogging of the screen are prevented. At the same time, a direct path ior the passage of the water to the well pipe is had so that no pockets or shelves or other places are formed in proximity to the crevices in the screen on which particles of sand might lodge to eventually clog the screen wall.

Changes in the various steps of my invention as herein disclosed may be made within the scope of what is claimed without departing from the spirit of my invention.

Having described my improved method, the apparatus for performing the same and the resuiting structure, what I claim as new and desire to protect my Letters Patent is:

l. The method of attaching a well screen wall element constructed with a dovetailed web to a supporting member, which consists in cutting a groove in the member in inserting the web of the element into the grooves, in cutting in said member a second groove adjacent said first groove, and in driving a wedge into said second groove, to force, the intervening portion of the body of the member against the dovetailed portion of the element.

2. The method of attaching well screen wall elements constructed with dovetailed webs to a supporting member which consists in cutting a groove in the member, in inserting the web of an element into the groove, in cutting in the member a second narrower groove adjacent said first groove, in driving a wedge into said second groove to force the intervening portion of the body of the member against the dovetail portion of the element, and in recutting said second groove to the form of said first groove for the repetitionoi the operation.

3. The method of forming a succession of dovetails in a metal rod which consists in forming the rod with a parallel walled groove, in wedging metal from the rod adjacent to one of the walls of the groove toward the other wall of the groove, and in recutting the wedged-out portion to form the next succeeding groove.

4. The method of forming well screens which consists in arranging a plurality of longitudinal supporting rods in cylindrical formation, in cutting a plurality of spaced grooves in all said rods, in coiling a formed wall element above said rods, in directing a portion thereof into one of said grooves, and in shifting the metal of the rods longitudinally from another of said grooves to lock the wall element in its groove.

5. The method of forming helical well screens which consists in arranging a plurality of longitudinal supporting rods in cylindrical formation, in progressively cutting a helical groove of predetermined pitch in said rods, in coiling a formed wall element about said rods and inserting the same into said groove, in distorting the rods progressively at localities in advance of said groove and spaced from said groove distances substantially equal to the pitch of said groove to urge the metal of the rods against the screen wall element and in removing the distorted portions of said rod in the further cutting of said groove. 6. The methodof forming helical well screens which consists in arranging a plurality of.longitudinal supporting rods in cylindrical formation, inprcgressively cutting a helical groove of predetermined pitch in said rods, in coiling a formed wall element about said rods and inserting. the same into said groove, in cutting a narrower helical groove in said rod in the path thereof and of the same pitch as said first groove and leading said first groove by a distance substantially equal to the pitch of said first groove, and in shifting the metal of the rods between the grooves away from the smaller groove and against the wall element in the first groove.

37. The method of forming helical well screens which consists in arranging a plurality of longitudinal supporting rods in cylindrical formation, in progressively cutting a helical groove of predetermined pitch in said rods, in coiling a formed wall element about said rods and inserting the same into said groove, in cutting a narrower helical groove in said rod in the path thereof and of the same pitch as said first groove and leading said first-groove by a distance substantially equal to the pitch of said first groove and in inserting a tool in the second groove to shift the metal of the rods between the two grooves against the wall element in the first groove.

8. The method of forming helical well screens which consists in arranging a plurality of longitudinal supporting rods in cylindrical formation, in simultaneously and progressively cutting two helical grooves of like pitch, in said rods, in coiling a formed wall element about said rods and in inserting the same into one of said grooves and in inserting the memberinto the other groove to shift the metal of said rods between said grooves against said wall element. a

9. The method of forming helical well screens which consists in arranging a plurality of longitudinal supporting rods in cylindrical'form-ation, in progressively cutting a helical groove of predetermined pitch in said rods, in coiling a formed wall element about said rods and insertingthe same into said groove, and in progressively distortingthe rods at localities in advance of said groove and spaced from said wall element to shift sections of the rod bodily against said wall element.

10. The method of forming a succession of dovetailed grooves in a metal rodwhich consists in forming the rod with a parallel walled groove adjacent the last formed dovetail groove, in distorting the metal of the rod beyondthe parallel walled groove and at a distance from the end wall thereof greater than the minimum thickness of the metal of the rod between the dovetailed grooves to cause a movement of the metal between said wall and the locality of distortion.

toward the opposite wall of the groove, in cutting succeeding parallel walled grooves and in repeat; ingthe operation of distortion after the cutting of each parallel walled groove.

11. The method of producing a.dovetaiI1lock" between a metal rod and a screen wall element which consists in forming a transverse groove in the rod, seating therein. a dovetailed element having an inclined side, in partially separating from the body of the rod adjacent the groove, a

portion defined by the wall of the groove next'tothe inclined side of the element and of substantially uniform thickness as measured from such face of the groove and in bendingthe portion so,

separated bodily about the base of the groove and against the inclined wall of the element.

12. The method of producing a dovetail lock between a metal rod and a screen wall element which consists in forming a transverse groove in the rod, seating therein a dovetailed element having an inclined side, in applying pressure longitudinally of the rod throughout the entire cross section of the portion of the rod adjacent the dovetailed element to bodily shift such portion substantially in a longitudinal direction and against said dovetailed element to lock the same in place.

13". The method of looking a screen wall element constructed with a dovetailed portion having an inclinedwall transversely to a metal rod which method consistsjin forming the rod with a parallel walled groove, seating the dovetailed portion of the screen wall element therein and in forcing a metal wedge with its working face next to the element substantially parallel to the inclined wall of the dovetailed portion of the screen element into the body of the rod adjacent the groove, whereby the intervening portion of the planiform wall inclined throughout its extent which consists in cutting a rectangular groove in said member and in forcing a wedge, having one face substantially parallel to the inclined side of the dovetailed slot to be formed, into the body of the rod to substantially the depth of the wall to tip one wall of the groove inwardly and toward the opposite wall. t

15. The method of forming a dovetailed groove in a metal rod which consists in forming the rod with a parallel walled groove, effecting a partial separation from the body of the rod of a portion of metal adjacent one wall of the groove of a depth substantially equal to the depth of the groove and in shifting said portion opposite wall of the groove. 16, The method of producing a dovetailed lock between a metal rod and a screen wall element having a dovetailed portion which consists in cutting a transverse parallel walled groove in the side of the rod, seating the dovetailed portion of the element therein, effecting axial separation of a portion of the body of the rod standing adjacent one wall of the groove to substantially the depth of the groove and forcing the portion so separated over against the dovetailed portion of the element ber adjacent said groove :1. portion defined by the a wall of the groove adjacent the inclined side of I the elementandof a thickness not exceeding the depthof the groove, and of aheight substantially equal'to thefdepth of the groove, and in forcing the, portion so separated bodily against the inclined wall; of the element.

, 18. The method of forming a succession of dovetailed grooves in a metal rod which consists in forming a rectangular groove in the rod, in cleaving from the body of the rod adjacent to one wall of the groove a standing portion defined by one wall of said groove and by the act' of cleaving said portion, Tchanging said portion from a substantially rectangular cross section to a substantially rhombic cross section tipped toward the opposite wall of the groove, and in 'recutting the cleavage opening to form the next succeeding groove.

19. The method of forming a dovetailed groove in a metal rod which consists in forming a rectangular groove in the rod, in forming a second groove in the rod adjacent the first groove and in the act of forming said second groove, shifting the intervening portion of the rod into the first named groove.

20. The method of forming a dovetailed groove in a metal rod, which consists in forming a rectangular groove in the rod, and in shifting the metal adjacent one wall of the groove toward the other wall of the groove, said shifting being uniformly decreased progressive from the outer end of the groove to bottom thereof to cause 'the shifted wall of the groove to become planiform upon completion of the shifting of the shifted portion of the rod.

- EDWARD E. JOHNSON.

toward the 20 

